Heretofore, it has been known that TiC is a high temperature bearing material having an excellent spalling resistance because it has high melting point, high hardness, and small coefficient of thermal expansion with its thermal conductivity remaining relatively constant even at high temperatures. However, TiC is a material which is scarcely capable of sintering, so that its compact sintered product could be obtained only as a cermet by adding a metal such as Co, Ni, etc.
Since the above-described cermet is a composite body which is governed by the behavior of the metallic phase, the above-described characteristics, especially the high temperature characteristics of the TiC itself cannot be optimally utilized.
For instance, in the cutting of ductile iron, the cermet tip utilizing the above-described cermet is used in the finish cutting, but even in the finish cutting, at high speed cutting such as of a cutting speed exceeding 300 m/min, the tip wears rapidly, showing considerable cratering wear, and further it is very subject to chipping. On the contrary, at a cutting speed less than from 150 to 200 m/min, deposition takes place resulting in the roughness of the finished surface, though not so serious as in the cemented carbide tip.